Synthetic audiovisual description scheme, method and system for mpeg-7

ABSTRACT

A method and system for description of synthetic audiovisual content makes it easier for humans, software components or devices to identify, manage, categorize, search, browse and retrieve such content. For instance, a user may wish to search for specific synthetic audiovisual objects in digital libraries, Internet web sites or broadcast media; such a search is enabled by the invention. Key characteristics of synthetic audiovisual content itself such as the underlying 2d or 3d models and parameters for animation of these models are used to describe it. To represent features of synthetic audiovisual content, depending on the description scheme to be used, a number of descriptors are selected and assigned values. The description scheme instantiated with descriptor values is used to generate the description, which is then stored for actual use during query/search.

The present application is a continuation of U.S. patent applicationSer. No. 12/648,988, filed Dec. 29, 2009, which is a continuation ofU.S. patent application Ser. No. 10/609,737, filed Jun. 30, 2003, nowU.S. Pat. No. 7,673,239, issued Mar. 2, 2010, which is a continuation ofSer. No. 09/495,171, filed Feb. 1, 2000, now U.S. Pat. No. 6,593,936,issued Jul. 15, 2003, which claims the benefit of U.S. ProvisionalApplication No. 60/118,023, filed Feb. 1, 1999, the contents of whichare incorporated herein by reference in their entirety.

This application includes an Appendix containing computer code thatperforms content description in accordance with the exemplary embodimentof the present invention. That Appendix of the disclosure of this patentdocument contains material that is subject to copyright protection. Thecopyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears inthe Patent and Trademark Office patent file or records, but otherwisereserves all copyright rights whatsoever.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention generally relates to audiovisual data processing.More particularly, this invention relates to the description ofsynthetic audiovisual content to allow such content to be searched orbrowsed with ease in digital libraries, Internet web sites and broadcastmedia.

2. Description of Related Art

More and more audiovisual information is becoming available from manysources around the world. Various forms of media, such as stillpictures, video, graphics, 3D models, audio and speech, may representsuch information. In general, audiovisual information plays an importantrole in our society, be it recorded in such media as film or magnetictape or originating, in real time, from some audio or visual sensors, beit analogue or, increasingly, digital. While audio and visualinformation used to be consumed directly by the human being,computational systems are increasingly creating, exchanging, retrievingand re-processing this audiovisual information. Such is the case forimage understanding, e.g., surveillance, intelligent vision, smartcameras, etc., media conversion, e.g., speech to text, picture tospeech, speech to picture, etc., information retrieval, e.g., quicklyand efficiently searching for various types of multimedia documents ofinterest to the user, and filtering to receive only those multimediadata items that satisfy the user's preferences in a stream ofaudiovisual content.

For example, a code in a television program triggers a suitablyprogrammed VCR to record that program, or an image sensor triggers analarm when a certain visual event happens. Automatic transcoding may beperformed based on a string of characters or audible information or asearch may be performed in a stream of audio or video data. In all theseexamples, the audiovisual information has been suitably “encoded” toenable a device or a computer code to take some action.

In the infancy of web-based information communication and accesssystems, information is routinely transferred, searched, retrieved andprocessed. Presently, much of the information is predominantlyrepresented in text form. This text-based information is accessed usingtext-based search algorithms. However, as web-based systems andmultimedia technology continue to improve, more and more information isbecoming available in a form other than text, for instance as images,graphics, speech, animation, video, audio and movies. As the volume ofsuch information is increasing at a rapid rate, it is becoming importantto be easily able to search and retrieve a specific piece of informationof interest. It is often difficult to search for such information bytext-only search. Thus, the increased presence of multimedia informationand the need to be able to find the required portions of it in an easyand reliable manner, irrespective of the search engines employed, havespurred on the drive for a standard for accessing such information.

The Moving Pictures Expert Group (MPEG) is a working group under theInternational Standards Organizationllnternational ElectrotechnicalCommission in charge of the development of international standards forcompression, decompression, processing and coded representation of videodata, audio data and their combination.

MPEG previously developed the MPEG-1, MPEG-2 and MPEG-4 standards, andis presently developing the MPEG-7 standard, formally called “MultimediaContent Description Interface”, hereby incorporated by reference in itsentirety. MPEG-7 will be a content representation standard formultimedia information search and will include techniques for describingindividual media content and their combination. Thus, the goal of theMPEG-7 standard is to provide a set of standardized tools to describemultimedia content. Thus, the MPEG-7 standard, unlike the MPEG-i, MPEG-2or MPEG-4 standards, is not a media-content coding or compressionstandard but rather a standard for representation of descriptions ofmedia content.

The data representing descriptions is called meta data. Thus,irrespective of how the media content is represented, e.g., analogue,PCM, MPEG-1, MPEG-2, MPEG-4, Quicktime, Windows Media etc., the metadata associated with this content, may in the future, be MPEG-7.

Often, the value of multimedia information depends on how easy it can befound, retrieved, accessed, filtered and managed. In spite of the factthat users have increasing access to this audiovisual information,searching, identifying and managing it efficiently is becoming moredifficult because of the sheer volume of the information. Moreover, thequestion of identifying and managing multimedia content is not justrestricted to database retrieval applications such as digital libraries,but extends to areas such as broadcast channel selection, multimediaediting and multimedia directory services.

Although known techniques for tagging audiovisual information allow somelimited access and processing based on text-based search engines, theamount of information that may be included in such tags is somewhatlimited. For example, for movie videos, the tag may reflect the name ofthe movie or a list of actors; however, this information must apply tothe entire movie and may not be sub-divided to indicate the content ofindividual shots and objects in such shots. Moreover, the amount ofinformation that may be included in such tags and architecture forsearching and processing that information is severely limited.

Additionally, image, video, speech, audio, graphics and animation arebecoming increasingly important components of multimedia information.While image and video are “natural” representations of a scene capturedby a scanner or camera, graphics and animation are “synthetic”representations of a scene often generated using parametric models on acomputer. Similarly, while speech and audio are natural representationsof “natural” sound captured using a microphone, text-to-speech orMusical Instrument Digital Interface (MIDI) are representations of“synthetic” sound generated via a model on a computer or computerizedsynthesizer. The synthetic audiovisual scenes may contain one or moretypes of synthetic objects, each represented by an underlying model andanimation parameters for that model. Such models may typically betwo-dimensional (2d) or three-dimensional (3d). For instance, data of awireframe model in three dimensions and a number of texture maps may beused to represent an F-15 fighter aircraft. This means that not only arealistic rendering of the F-15 is possible using this data but thatthis amount of data is sufficient to either synthesize any view of F-15or interact with it in three dimensions. Due to popularity of such 3dcontent on the web, a textual language for representation of 3d modelsand their animation has been standardized by ISO and is called VirtualReality Modeling Language (VRML). However, this language is designed ata very low level and, although it is quite useful for synthesis of 3dcontent, it may not be fully appropriate for its description in the waysusers might want to query for such content.

SUMMARY OF THE INVENTION

Despite the increasing number databases of such content and usersneeding the ability to search these databases to find something forwhich they are looking, search and retrieval of synthetic audiovisualcontent remains a significant challenge which is yet to be addressed ina satisfactory manner. In actuality, search for synthetic content can beperformed either in the rendered domain or in its original (model andanimation parameters) domain. Searching in the rendered domain is infact very similar to searching for images and video and is therefore,not the primary focus of this invention.

Rather, this invention improves searching capabilities in the originaldomain. Within the context of requirements of proposals for the MPEG-7standard, this invention addresses this challenge and proposes a systemand a method for processing and description of synthetic audiovisualdata to make it easy to search and browse.

Accordingly, the present invention addresses the need for describingsynthetic audiovisual information in a way that allows humans, softwarecomponents or devices to easily identify, manage and categorize it. Sucha manner of describing synthetic audiovisual content data allows ease ofsearch by a user who may be interested in locating a specific piece ofsynthetic content from a database, Internet, or broadcast media.Moreover, in another application of the manner of describing syntheticaudiovisual content, an automated information processing device may beable to locate the unique features of synthetic audiovisual content in adatabase or detected in a broadcast and take the necessary actions suchas filter, collect, manage or record it.

The exemplary embodiment of the present invention provides a system andmethod that describes information in such a way that characteristics ofsynthetic audiovisual information are more easily searched, located andpresented. More particularly, when describing an audiovisual scene, thescene may be partitioned into individual objects and their spatial andtemporal relationships. Further, a description or meta data may beassociated with the synthetic objects in the scene in accordance withthis invention. Therefore, the invention is directed at providing amethod and a system for describing synthetic audiovisual content.

The method and system of this invention make it easier to search, browseand retrieve synthetic audiovisual content. For instance a user may wishto search for specific synthetic audiovisual objects in digitallibraries, Internet web sites or broadcast media. Key characteristics ofsuch content itself are employed to facilitate this. Since syntheticaudiovisual content is usually generated using various types of 2d or 3dmodels and by defining animation parameters of these models, thefeatures of these models and animation characteristics that apply tothese features are used for describing the content. The syntheticaudiovisual content and its descriptions may then be processed foreither direct human consumption or sent to devices, e.g., computers,within a system, or sent over a network, e.g., the Internet, and easilyaccessed and utilized.

The exemplary embodiment of the present invention addresses the draftrequirements of MPEG-7 promulgated by MPEG at the time of the filing ofthis patent application. That is, the present invention providesobject-oriented, generic abstraction and uses objects and events asfundamental entities for description. Thus, the present inventionprovides an efficient framework for description of various types ofsynthetic visual data. The present invention is a comprehensive tool fordescribing synthetic visual data because it uses eXtensible MarkupLanguage (XML), which is self-describing. The present invention alsoprovides flexibility because parts can be instantiated so as to provideefficient organization. The present invention also providesextensibility and the ability to define relationships between databecause elements defined in a Description Scheme (DS) can define newelements.

These and other features and advantages of this invention are describedin or are apparent from the following detailed description of the systemand method according to this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The benefits of these objects of the present invention will be readilyappreciated and understood from consideration of the following detaileddescription of the exemplary embodiment of this invention, when takentogether with the accompanying drawings, in which:

FIG. 1 is a high level representation illustrating the use ofdescriptors and description according to principles of the invention;

FIG. 2 is a schematic representation in UML (Unified Modeling Language)of a relation between audiovisual scene DS and synthetic audiovisualmodel DS according to the exemplary embodiment of the invention;

FIG. 3 is a schematic representation in UML of a synthetic audiovisualmodel DS in XML illustrating its elements and their relationshipsaccording to the exemplary embodiment of the invention;

FIG. 4 is a schematic representation in UML of an audio animation eventmodel DS in XML illustrating its elements and their relationshipsaccording to the exemplary embodiment of the invention;

FIG. 5 is a schematic representation in UML of a visual animation eventmodel DS in XML illustrating its elements and their relationshipsaccording to the exemplary embodiment of the invention;

FIG. 6 is a schematic representation in UML of an audio animation objectmodel DS in XML illustrating its elements and their relationshipsaccording to the exemplary embodiment of the invention;

FIG. 7 is a schematic representation in UML of a visual animation objectmodel DS in XML illustrating its elements and their relationshipsaccording to an exemplary embodiment of the invention;

FIG. 8 illustrates a method for generation of descriptions in accordancewith the exemplary embodiment of the invention; and

FIG. 9 illustrates a system for generation and use of syntheticaudiovisual content descriptions that implements the exemplaryembodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Prior to explaining the exemplary embodiment of the invention, a briefsynopsis of MPEG-7 is provided to aid in the reader's understanding ofhow the exemplary embodiment processes synthetic visual data within theconstruct of MPEG-7.

MPEG-7 is directed at providing a standard that allows quick andefficient searching for various types of multimedia material interestingto the user. MPEG-7 is meant to provide standardization of multimediacontent descriptions. MPEG-7 expects to extend the limited capabilitiesof proprietary solutions in identifying content that exist today,notably by including multimedia data types. In other words, MPEG-7 willspecify a standard set of descriptors that can be used to describevarious types of multimedia information. MPEG-7 will also specifypredefined structures of descriptors and their relationships, as well asways to define one's own structures. These structures are calleddescription schemes (DSs). Defining new DSs can be performed using aspecial language, the Description Definition Language (DDL), which isalso a part of the MPEG-7 standard. A description, i.e., a set ofinstantiated DSs is associated with data content itself to allow fastand efficient searching for material of a user's interest. MPEG-7 willalso include coded representations of a description for efficientstorage, or fast access.

Conventionally, search engines each have individual syntax formats thatdiffer. These differences in syntax format cause compatibility issuesbetween search criteria, e.g., identical criteria used by differentengines results in different results. With the use of DSs under MPEG-7,these search engines will be able to process MPEG-7 multimedia contentregardless of the differing syntax formats to produce the same results.The requirements of MPEG-7 apply, in principle, to both real-time andnon-real time applications. Also, MPEG-7 will apply to push and pullapplications. However, MPEG7 will not standardize or evaluateapplications. Rather, MPEG-7 will interact with many differentapplications in many different environments, which means that it willneed to provide a flexible and extensible framework for describingmultimedia data. Therefore, MPEG-7 will not define a monolithic systemfor content description. Rather, MPEG-7 will define a set of methods andtools for describing multimedia data. Thus, MPEG-7 expects tostandardize a set of descriptors, a set of DSs, a language to specifyDSs (and possibly descriptors), e.g., DDL, and one or more ways toencode descriptions.

A starting point for DDL is the XML, although it is expected that thebasic XML will eventually need to be customized and modified for use inMPEG-7.

The exemplary embodiment of the invention described herein withreference to FIGS. 1-9 conforms to the requirements of the MPEG-7standard, in its present form. However, it should be appreciated andforeseeable to one of ordinary skill in the art that the exemplaryembodiment of the invention will conform to additional and differentrequirement of the formal MPEG-7 standard, once it has been adopted,without departing from the scope of the invention.

The following description of the description of exemplary embodiment ofthe invention uses terminology that is consistent with definitionsprovided in the MPEG-7 call for proposals document. The term “data”indicates audiovisual information that is described using MPEG-7,regardless of storage, coding, display, transmission, medium ortechnology. Data encompasses, for example, graphics, still images,video, film, music, speech, sounds, text and any other relevantaudiovisual medium. Examples of such data may be found in, for example,an MPEG-4 stream, a videotape, a compact disc containing music, sound orspeech, a picture printed on paper or an interactive multimediainstallation on the World Wide Web.

A “feature” indicates a distinctive characteristic of the data thatsignifies something to someone. Examples of features include imagecolor, speed pitch, audio segment rhythm, video camera motion, videostyle, movie title, actors names in a movie, etc. Examples of featuresof visual objects include shape, surface, complexity motion, light,color, texture, shininess and transparency.

A “descriptor” is a representation of a feature. It is possible to haveseveral descriptors representing a single feature. A descriptor definesthe syntax and the semantics of the feature representation. A descriptorallows the evaluation of the corresponding feature via the descriptorvalue. Examples of such descriptors include color histogram, frequencycomponent average, motion field, title text, etc.

A “descriptor value” is an instantiation of a descriptor for a givendata set. Descriptor values are combined using a DS to form adescription.

A “description scheme”, DS, specifies the structure and semantics ofrelationships between its components, which may be both descriptors andDSs. The distinction between a DS and a descriptor is that a descriptorcontains only basic data types, as provided by the DDL. A descriptoralso does not refer to another descriptor or DS. Examples of DSs includemovies that include temporally structured data as scenes and shots,including some textual descriptors at the scene level, and color, motionand some audio descriptors at the shot level.

A “description” includes a DS and the set of descriptor values thatdescribe the data. Depending on the completeness of the set ofdescriptor values, the DS may be fully or partially instantiated.Additionally, it is possible that the DS may be merely incorporated byreference in the description rather than being actually present in thedescription. A “coded description” is a description that has beenencoded to fulfill relevant requirements such as compression efficiency,error resilience, random access, etc. The description definitionlanguage, or DDL, is the language that allows the creation of new DSsand, possibly, new descriptors. The DDL also allows the extension andmodification of existing DSs.

MPEG-7 data may be physically located with the associated audiovisualmaterial, in the same data stream or on the same storage system, but thedescriptions can also be stored elsewhere. When the content and itsdescriptions are not co-located, mechanisms that link audiovisualmaterial and their MPEG-7 descriptions are needed; these links must workin both directions.

As mentioned above, the exemplary embodiment of the invention provides aDS for synthetic visual content synthetic visual content relates toartificial visual objects, such as facial animation or graphics used inmultimedia. synthetic visual content data is generated by animatingvisual objects defined by a virtual wireframe and a texture map.Animation is provided to move the visual objects using an animationstream for nodes of the virtual wireframe. These animation stream nodescan be linked to visual contents such as, for example, the type ofwireframe, reference to the wireframe within a library of thousands ofwireframes, wireframe parameters, reference to a texture map, parametersof the texture map, parameters of the animation stream, etc.

Also as mentioned above, the exemplary embodiment meets the MPEG-7requirements outlined in the present draft of MPEG-7 standardrequirements. Requirements include criteria relating to descriptors, DSsrequirements, DDL requirements and system requirements. While theexemplary embodiment of the invention should satisfy all requirements ofMPEG-7 when taken as a whole, not all requirements have to be satisfiedby each individual descriptor or DS. The descriptor requirements includecross-modality, direct data manipulation, data adaptation, language oftext-based descriptions, linking, prioritization of related informationand unique identification. DS requirements include DS relationships,descriptor prioritization, descriptor hierarchy, descriptor scalability,temporal range description, data adaptation, compositional capabilities,unique identification, primitive data types, composite data types,multiple media types, various types of DS instantiations, relationshipswithin a DS and between DSs, relationship between description and data,links to ontologies, platform independence, grammar, constraintvalidation, intellectual property management and protection, humanreadability and real time support.

While a DS can be generated using any DDL, the exemplary embodiment ofthe invention uses eXtensible Markup Language (XML) to represent thesynthetic visual DS. The synthetic visual DS includes several basiccomponents: objects, animation streams and object feature structures.XML is a useful subset of SGML. XML is easier to learn, use andimplement than SGML. XML allows for self-description, i.e., allowsdescription and structure of description in the same format anddocument. Use of XML also allows linking of collections of data byimporting external document type definitions using DSs.

Additionally, XML is highly modular and extensible. XML provides aself-describing and extensible mechanism, and although notmedia-centric, can provide a reasonable starting basis. Another majoradvantage of using XML is that it allows the descriptions to beself-describing, in the sense that they combine the description and thestructure of the description in the same format and document. XML alsoprovides the capability to import external Document Type Definitions(DTDs), e.g., for feature descriptors, into the image DS DTD in a highlymodular and extensible way.

According to the exemplary embodiment of the invention, each syntheticaudiovisual description can include synthetic audio or visual objects.Each synthetic visual object can be associated with an animation stream.Each synthetic visual object has one or more associated syntheticfeatures. The synthetic features of an object are grouped together asbeing visual, audio or a relationship on semantic or media. In thesynthetic visual DS, each feature of an object has one or moreassociated descriptors.

The synthetic visual DS also includes specific DTDs, also generatedusing the XML framework, to provide example descriptors. The DTDprovides a list of the elements, tags, attributes, and entitiescontained in the document, and their relationships to each other. DTDsspecify a set of rules for the structure of a document. For example, aDTD specifies the parameters needed for certain kinds of documents.Using the synthetic visual DS, DTDs may be included in the file thatcontains the document they describe. In such a case, the DTD is includedin a document's prolog after the XML declaration and before the actualdocument data begins. Alternatively, the DTD may be linked to the filefrom an external URL. Such external DTDs can be shared by differentdocuments and Web sites. In such a way, for a given descriptor, thesynthetic visual DS can provide a link to external descriptor extractioncode and descriptor similarity code.

The DS provides flexibility by allowing components of the DS to beinstantiated, using efficient categorization of features and supportingefficient linking, embedding, or downloading of external featuredescriptor and execution codes. Elements defined in the synthetic visualDS can be used to derive new elements. Further, the synthetic visual DSis closely related to other elementary media DS, e.g., image DS, videoDS, and included in the DS for multimedia, e.g., integration DS.

One unique aspect of the synthetic visual DS is the capability to definemultiple abstraction levels based on a chosen criterion. The criteriacan be specified in terms of visual features, e.g., size, semanticrelevance, e.g., relevance to a user's interest profile, or servicequality, e.g., media features.

There are two basic cases in which synthetic visual content must bedescribed to facilitate search and retrieval. In a first case, thesynthetic visual content is assumed to be pre-rendered. In a secondcase, a description of unrendered content is described to facilitatesearch and retrieval. The exemplary embodiment of the invention servesto describe such unrendered content. Therefore, the synthetic visual DSis designed to describe MPEG-4 synthetic visual content and VRML contenteffectively.

DTDs of synthetic visual DSs can be designed and created using XML. Adocument type definition provides a list of the elements, tags,attributes, and entities contained in the document, and theirrelationships to each other. Description schemes specify a set of rulesfor the structure of a document. Description schemes may be included inthe file that contains the document they describe, or they may be linkedto form an external URL. Such external DSs can be shared by differentdocuments and Web sites. A DS may be included in a document's prologafter the XML declaration and before the actual document data begins.

Audiovisual material that has MPEG-7 data associated with it, mayinclude still pictures, graphics, 3D models, audio, speech, video, andinformation about how these elements are combined in a multimediapresentation, i.e., scenario composition information. A special case ofthis general data type may include facial expressions and personalcharacteristics.

FIG. 1 is a high level representation illustrating the use ofdescriptors and description according to principles of the invention. Asshown in FIG. 1, a synthetic audiovisual content description generator130 uses synthetic audiovisual content DS provided by syntheticaudiovisual DS unit 140 to provide synthetic audiovisual contentdescription 150 to a search engine 160. This search engine 160 hasaccess to the synthetic audiovisual content 100 directly as well. Thesynthetic audiovisual content description 150 provides a way of indexingthe synthetic audiovisual content 100.

On-line operation of the search engine 160 to provide search results inresponse to a content query is explained below in detail with referenceto FIG. 9. In contradistinction, FIG. 1 illustrates the off-lineprocessing of synthetic audiovisual data 100. Specifically, the featureextractor and representor 110 represent the synthetic audiovisual data100, using descriptors. These descriptors are determined based on thesynthetic audiovisual DS supported by the synthetic audiovisual DS unit140. Different descriptors may be selected depending on the selectedsynthetic audiovisual DS. The feature extractor and representor 110produce descriptor values 120 indicative of the synthetic audiovisualcontent 100.

The descriptor values 120 are input to the synthetic audiovisual contentdescription generator 130, which generates content description 150 basedon the descriptor values 120 and the synthetic audiovisual DS supportedby the synthetic audiovisual DS unit 140. Thus, the content description150 is generated off-line, e.g., at a convenient or arbitrary time thatmay or may not be related to synthetic audiovisual data downloading froma database or a broadcast.

The above explanation refers to a synthetic audiovisual DS supported bythe synthetic audiovisual DS unit 140 because the generator 130 mayrefer to various DSs that may be provided by vendors of syntheticaudiovisual data content 100 or by others.

FIG. 2 is a schematic representation in UML of a relation between anaudiovisual scene DS 200 and synthetic audiovisual model DS 220according to the exemplary embodiment of the invention. As shown in FIG.2, the audiovisual scene DS 200 can incorporate, i.e., aggregate, anatural audiovisual scene DS 210, a synthetic audiovisual model DS 220,a scene description DS 230 and scene descriptors 240. The audiovisualscene DS 200 may incorporate any of the elements 220-240 but is notrequired to include any of them. Therefore, elements 220-240 may beincorporated in various combinations within the audiovisual scene DS200. More specifically, the audiovisual scene DS 200 may incorporate anyquantity of natural audiovisual scene DSs 210 and synthetic audiovisualmodel DSs 220. However, the audiovisual scene DS 200 may eitherincorporate no scene description DS 230 or one scene DS DS 230. Thescene description DS 230 incorporates at least one scene descriptor 240.The synthetic audiovisual model DS 220 and the natural audiovisual sceneDS 210 may also be linked to the scene descriptors 240.

FIG. 3 is a schematic representation of a synthetic audiovisual model DS220 in UML illustrating its elements and their relationships accordingto the exemplary embodiment of the invention. As shown in FIG. 3, thesynthetic audiovisual model DS 220 may incorporate an animation event DS310, an animation object DS 320 and an animation event/object relationDS 330; synthetic audiovisual model DS 220 may incorporate any number oreach of elements 310-330 or incorporate none of each of them. Thesynthetic audiovisual model DS 220 incorporates DSs that correspond toboth static and dynamic characteristics. Specifically, the animationevent DS 310 corresponds to dynamic characteristics, e.g., changingfacial expression of computer generated face model, movement of a carmodel. The animation object DS 320 corresponds to staticcharacteristics, e.g., definition parameters of face, color of that carmodel. The animation event/object relation DS 330 corresponds tosynthetic audiovisual data related to the relationship between animationobjects and animation events.

The animation event DS 310 may incorporate any number of each of theaudio animation event model DSs 340 and visual animation event model DSs350. That is, the animation event DS 310 may incorporate elements 340and 350 in any number.

The animation object DS 320 may incorporate any number of each of theaudio animation object model DSs 360 and visual animation object modelDSs 370. That is, the animation object DS 320 may incorporate each ofelements 360 and 370 in any number.

FIG. 4 is a schematic representation of an audio animation event modelDS 340 in UML illustrating its elements and their relationshipsaccording to the exemplary embodiment of the invention. As shown in FIG.4, the audio animation event model DS 340 may incorporate an audioanimation stream model DS 410. The audio animation stream model DS 410may incorporate a number of each of a structured audio animation streammodel DS 420, a Text To Speech (TTS) stream model DS 430 and a BInaryFormat for scenes (BIFS) audio animation stream model DS 440. That is,the audio animation stream model DS 410 may incorporate each of elements420-440 in any number.

The structured audio animation stream model DS 420 may be, for example,MIDI. The BIFS audio animation stream model DS 440 is an MPEG-4 scenedescription and is similar to a DS generated using VRML but BIFS is itsbinary version. The Appendix includes computer code in XML including anexample of a structured audio animation stream model DS 420, a TTSanimation stream model DS 430 and a BIFS audio animation stream model DS440.

FIG. 5 is a schematic representation of a visual animation event modelDS 350 in UML illustrating its elements and their relationshipsaccording to the exemplary embodiment of the invention. As shown in FIG.5, the visual animation event model DS may incorporate any number ofvisual animation stream model DSs 510. A visual animation stream modelDS 510 may incorporate any number of each of a face animation streammodel DS 520, a body animation stream model DS 530, a mesh animationstream model DS 540, a sprite animation stream model DS 550 and a BIFSvisual animation stream model DS 560. The Appendix also includescomputer code in XML including an example of a face animation streammodel DS 520, a body animation stream model DS 530, a mesh animationstream model DS 540 a sprite animation stream model DS 550 and a BIFSvisual animation stream model DS 560.

FIG. 6 is a schematic representation of an audio animation object modelDS 360 in UML illustrating its elements and their relationshipsaccording to the exemplary embodiment of the invention. As shown in FIG.6, the audio animation object model DS 360 may incorporate any number ofeach of a structured animation object model DS 610, a TTS animationobject model DS 620 and a BIFS audio object model DS 630. That is, theaudio animation object model DS 360 may incorporate each of elements610-630 in any number. The Appendix also includes computer codeincluding an example of a structured audio animation object model DS610, a TTS animation object model DS 620 and a BIFS audio object modelDS 630.

FIG. 7 is a schematic representation of a visual animation object modelDS 370 in UML illustrating its elements and their relationshipsaccording to an exemplary embodiment of the invention. As shown in FIG.7, the visual animation object model DS 370 may incorporate any numberof each of a face animation object model DS 710, a body animation objectmodel DS 720, a mesh animation object model DS 730, sprite animationobject model DS 740, a BIFS visual animation object model DS 750 and avisual properties DS 760. That is, the visual animation object model DS370 may incorporate each of elements 710-760 in any number. The Appendixalso includes computer code including an example of a face animationobject model DS 710, a body animation object model DS 720, a meshanimation object model DS 730, sprite animation object model DS 740, aBIFS visual animation object model DS 750 and a visual properties DS760.

Additionally, Table 1 includes further information about the visualproperties DS 760. Specifically, the visual properties DS 760 mayinclude features such as location, text annotation, synthetic shapesynthetic surface(s), synthetic complexity, synthetic motion(s)synthetic event input/output(s) and synthetic light(s). Table 1 alsoincludes additional information about the descriptors that may be useddefine these features. For example, the feature of synthetic shape mayinclude normal histogram descriptors, synthetic silhouette descriptorsor three dimensional bounding box descriptors.

TABLE 1 Element Must Contain May Contain Must Be Contained inVisProperties location (root element) text_annotation syn_shapesyn_surface(s) syn_complexity syn_motion(s) syn_event 1/0(s)syn_light(s) syn_shape normal histogram VisProperties syn_silhouette3D_bounding_box syn_silhouette shape syn_shape angle syn_surface imageVisProperties video color specular_color shininess transparencysyn_complexity num_transform VisProperties num_scripts num_polygon_equivnum_routes num_interpolators syn_motion ego_motion VisPropertiessyn_eventI/O sensors VisProperties light directional VisProperties pointspot ambient color

Tables 2 and 3 include additional information about the face and bodyanimation object model DSs 710 and 720. Specifically, Table 2 shows thatone example of the face animation object model DS 710 may includedescriptors relating to gender, person identification, tongueinformation teeth information glasses and hair, as well as a TTSinterface, a facial animation parameter (FAP) interface, a FAP interfacea FAP stream. Similarly, one example of the body animation object modelDS 730 may include descriptors relating to gender, personidentification, number of joints, number of hand joints, number of spinejoints, and clothes as well as a body animation parameters (BAP)interface and a BAP stream. Table 3 provides further information aboutthe contents of the FAP and BAP streams.

TABLE 2 Must Must Be Element Contain May Contain Contained inFaceAnimObjModel gender VisAnimObjModel person_id TTS_interface FAP_interface FAP stream_ tongue teeth glasses hair BodyAnimObjModel genderVisAnimObjModel person_id BAP_interface BAP stream num joints num_ handjoints num_spine joints clothes

TABLE 3 Element Must Contain May Contain Must Be Contained in FAP streamexpressions FaceAnimObjModel visemes low_level_FAP text_ annotationlocation BAP_stream body_BAP BodyAnimObjModel hand BAP text_ annotationlocation

FIG. 8 illustrates a method for generation of descriptions in accordancewith the exemplary embodiment of the invention. The method illustratedin FIG. 8 is preferably performed off-line and not in real-time. Asshown in FIG. 8, the method begins in step 800 and proceeds to step 810.In step 810, synthetic audiovisual content is obtained from a databaseor broadcast data and control proceeds to step 820. In step 820,features are selected to be extracted from the synthetic audiovisualcontent. For example, selected features may include model types, modelparameters, animation and relation with other models. Control theproceeds to step 830, in which the selected features are mapped todescriptors supported by the selected synthetic audiovisual DS.

The descriptors are selected based on the synthetic audiovisual DSselected for the describing the synthetic audiovisual content obtainedin step 810. Control then proceeds to steps 840 and 850. In step 840,the selected synthetic audiovisual DS is accessed. In step 850, featuresof the synthetic audiovisual content are extracted and represented usingselected descriptor values consistent with the selected syntheticaudiovisual DS. Preferably, steps 840 and 850 are performedsimultaneously for the purpose of efficiency; however, it should beappreciated that steps 840 and 850 may be performed in any order inrelationship to each other.

Following completion of both steps 840 and 850, control proceeds to step860. In step 860, the selected synthetic audiovisual DS is instantiatedwith the descriptor values generated in step 850 to generate syntheticaudiovisual descriptions corresponding to the synthetic audiovisualcontent obtained in step 810. Control then proceeds to step 870, inwhich the generated synthetic audiovisual descriptions are stored. Thegenerated synthetic audiovisual descriptions may be stored with thecorresponding synthetic audiovisual content or stored remotely from andlinked to the corresponding synthetic audiovisual content. Control thenproceeds to step 880, in which the method for off-line generation ofcontent descriptions ends.

FIG. 9 illustrates a system for generation as well as use of syntheticaudiovisual content descriptions that implements the exemplaryembodiment of the invention. As shown in FIG. 9, the system may includea server 900 coupled to a client terminal 940 via a network 930. Theserver may incorporate a search engine 910, a synthetic audiovisualcontent database 920, a descriptions database 930 a pseudo features topseudo description converter 905 and a feature extractor, representor bydescriptor and description generator 960. The synthetic audiovisualcontent database 920 and the descriptions database 930 may be coupled toone another via, for example, a physical or a logical link. The clientterminal 940 may include a query interface and search tools 950 and asynthetic audiovisual content browser 970. The feature extractor,representor by descriptors and description generator 960 corresponds toall of the elements 110-130 illustrated in FIG. 1.

It is important to appreciate that FIG. 9 illustrates an example ofarchitecture that may utilize the exemplary embodiment of the invention.Additionally, FIG. 9 illustrates processing actions performed by thisarchitecture both on-line and off-line. Specifically, FIG. 9 illustratesthe use of a DS 965 to perform feature extraction and representation bydescriptors and description generation. These processing actions areperformed based on the synthetic audiovisual content stored in thedatabase 920 and the DS 965. The resulting generated descriptions arestored in the descriptions database 930. As illustrated in FIG. 9, theseprocessing actions are performed off-line.

In contradistinction, remaining actions performed by architectureillustrated in FIG. 9 are performed on-line. For example, when a userinputs a synthetic audiovisual data query through the query interfaceand search tools 950, the search tools send the query to a query topseudo features converter 945 that maps the query to pseudo features andsubmit the pseudo features to the server 900 over the network 930. Thenetwork 930 may be a public or private network, for example, anyconventionally known intranet or the Internet. Once received in theserver 900, the pseudo features are converted to pseudo descriptionusing the pseudo features to pseudo description converter 905. Thesearch engine 910 uses the pseudo description to access the descriptionsstored in the descriptions database 930. The search engine 910 thenretrieves synthetic audiovisual content stored in database 920 andassociated with a description(s) stored in the database 930 that mostclosely match the pseudo description. The search engine 910 thanprovides the retrieved synthetic audiovisual content to the clientterminal via the network 930, the synthetic audiovisual content browser970 and the query interface and search tools 950.

Although FIG. 9 illustrates the converters 905 and 945 as separateelements at different physical locations, it should be appreciated thatthe converters may be a single element located at the server 900, theclient terminal 940 or a remote location in the network 930.

The client terminal 940 may be, for example, a personal computer or adigital VCR that receives an audiovisual stream including syntheticaudiovisual data, such as a computer animation model and instructions toanimate it, e.g., a digital TV program, and descriptions of theaudiovisual information associated with the program. Incorporation ofdescriptions within the audiovisual stream may allow the digital VCR torecord, for example, only news with the exclusion of sport. By utilizingthe synthetic audiovisual DS, products can be described in such a waythat a client terminal 940 can respond to unstructured queries fromusers making the queries.

While this invention has been described in conjunction with theexemplary embodiment outlined above, it is evident that manyalternatives, modifications and variations will be apparent to thoseskilled in the art. Accordingly, the exemplary embodiment of theinvention, as set forth above, is intended to be illustrative, notlimiting. Various changes may be made without departing from the spiritand scope of the invention.

For example, an emerging standard from W3C, XML, has been used torepresent the DS, although any specific DDL selected by MPEG-7 can beused to serve the same purpose as well.

Additionally, it is important to understand that the specific algorithmused for feature extraction during the description generation process isoutside the scope of MPEG-7 standardization. Therefore, any conventionalalgorithm for feature extraction may be used. Leaving the algorithmundefined enables the exemplary embodiment of the invention toaccommodate technological developments in feature extraction andencourage competitive MPEG-7 development.

What is claimed is:
 1. A method comprising: receiving audiovisual data;representing a synthetic feature of the audiovisual data having adefined animation parameter as a descriptor, wherein the descriptor isselected according to a synthetic audiovisual description scheme thatspecifies a structure and semantics of relationships between componentsof the audiovisual data; assigning, via a processor, a value to thedescriptor based on the synthetic feature; and generating a descriptionbased on the value of the descriptor, wherein the description comprisesspatial and temporal relationships of audiovisual objects in a scene. 2.The method of claim 1, wherein the components comprise other constituentdescription schemes.
 3. The method of claim 2, wherein the otherconstituent description schemes comprise an animation event descriptionscheme corresponding to dynamic characteristics of the audiovisual data.4. The method of claim 2, wherein the constituent description schemescomprise an animation object description scheme corresponding to staticcharacteristics of the audiovisual data in the scene.
 5. The method ofclaim 2, wherein the constituent description schemes comprise ananimation event and a relational description scheme.
 6. The method ofclaim 1, wherein the synthetic feature is a model feature used togenerate the audiovisual data.
 7. The method of claim 6, wherein themodel feature comprises one of a two-dimensional model and athree-dimensional model.
 8. The method of claim 1, wherein eachaudiovisual object in the audiovisual objects is associated withsynthetic features.
 9. The method of claim 8, wherein the syntheticfeatures of an audiovisual object are grouped together as being one ofvisual, audio, and a relationship of-media.
 10. The method of claim 1,wherein each audiovisual object in the audiovisual objects is associatedwith an animation stream
 11. The method of claim 1, wherein the value isan instantiation of the descriptor corresponding to the audiovisualdata.
 12. The method of claim 1, wherein the representing, the assigningand the generating are performed using extensible markup language. 13.The method of claim 1, wherein the synthetic audiovisual descriptionscheme comprises a document type definition that provides a list ofexample descriptors used during the representing.
 14. The method ofclaim 13, wherein the document type definition specifies a set of rulesfor a structure of the audiovisual data.
 15. The method of claim 1,wherein the description comprises the value and is associated with thesynthetic audiovisual description scheme.
 16. The method of claim 15,wherein the synthetic audiovisual description scheme is incorporated inthe description.
 17. The method of claim 16, wherein the syntheticaudiovisual description scheme is stored at a remote location and thedescription is linked to the synthetic audiovisual description scheme.18. The method of claim 17, wherein a device at the remote location isaccessible over a network.
 19. A system comprising: a processor; and acomputer-readable storage medium having instructions stored which, whenexecuted by the processor, result in operations comprising: receivingaudiovisual data; representing a synthetic feature of the audiovisualdata having a defined animation parameter as a descriptor, wherein thedescriptor is selected according to a synthetic audiovisual descriptionscheme that specifies a structure and semantics of relationships betweencomponents of the audiovisual data; assigning a value to the descriptorbased on the synthetic feature; and generating a description based onthe value of the descriptor, wherein the description comprises spatialand temporal relationships of audiovisual objects in a scene.
 20. Acomputer-readable storage device having instructions stored which, whenexecuted by a computing device, result in operations comprising:receiving audiovisual data; representing a synthetic feature of theaudiovisual data having a defined animation parameter as a descriptor,wherein the descriptor is selected according to a synthetic audiovisualdescription scheme that specifies a structure and semantics ofrelationships between components of the audiovisual data; assigning avalue to the descriptor based on the synthetic feature; and generating adescription based on the value of the descriptor, wherein thedescription comprises spatial and temporal relationships of audiovisualobjects in a scene.